1. Field of the Invention
The present invention relates generally to fluid transport piping systems. More particularly, the invention comprises a portable compression system for pipeline purging that provides recovery of combustion gases for the purpose of creating a high pressure non-combustible gas for use in purging of gas pipelines, oil pipelines and pipelines of hydrocarbon producing factories. The current invention is innovative and will find application in various pipeline construction industries.
In general, the disclosed invention is described as it relates to the field of gas pipeline, oil pipeline and hydrocarbon producing factories pipeline purging. However, the invention is applicable to any task in which it is desired to clear pipelines, so that the pipelines can be repaired or replaced when needed.
Thus, it can be seen that the potential fields of use for this invention are myriad and the particular preferred embodiments described herein is in no way meant to limit the use of the invention to the particular field chosen for exposition of the details of the invention.
A comprehensive listing of all the possible fields to which this invention may be applied is limited only by the imagination and is therefore, not provided herein. Some of the more obvious applications are mentioned in the interest of providing a full and complete disclosure of the unique properties of this previously unknown general purpose article of manufacture. It is to be understood from the outset that the scope of this invention is not limited to these fields or to the specific examples of potential uses presented herein.
2. Description of the Prior Art
Within the natural gas transmission industries it is often required that sections of pipelines be removed from service and repaired before they are returned to service. These events are most commonly pre-planned and part of an elaborate long term maintenance program. Historically, this has meant that a pipe section consisting of many miles (twenty miles or greater) of large diameter pipe (twenty four inches to forty eight inches) at high pressure (one thousand pounds per square inch and greater) is isolated and simply blown down creating a large release of natural gas to the atmosphere. The issue is the substantial loss of natural gas and the related value, the significant release of a potent green house gas and duration of the loss of use of the pipeline during this down time.
The industry has largely recognized the impact of green house gases and has adapted several practices to reduce this impact. One practice is to burn the natural gas thus converting the gas to the less damaging carbon dioxide. The other method is to utilize pull down compression to draw gas out of the isolated section and deliver it to an adjacent pipeline section. Both of these methods to mitigate the problem are time consuming and require specialized expensive equipment. Because of downtime constraints of modern facilities, utilizing these methods have only been partially successful and large volumes of gas inventory are wasted and gas emissions directed into the atmosphere.
It would be conceivable to displace the natural gas in a section with another substance, however, there exist obstacles. Purging the gas from the system with compressed air is technically feasible, but the introduction of oxygen into a hydrocarbon vessel would create the very undersible potential for an explosion. This is unacceptable. An inert substance such as nitrogen to displace the gas would again be feasible, but the cost and extended time to achieve a major purge would be unacceptable.
With oil transmission systems there exists a somewhat similar situation in that pipelines require a periodic repair program to facilities which are large diameter, high pressure and sections are long, requiring the vacating of large volumes of oil. Unlike gas pipelines, the vacating of the pipeline cannot include the release of product to the environment. Like gas pipelines, duration of a shut down is critical to the pipeline owner. The most common methods of displacing oil from the pipeline is to drain down the pipeline or purge the pipeline with an inert medium such as nitrogen. Again, air is an unacceptable purge medium. The cost of nitrogen being excessive and not available in large quantities, the owner is forced to balance cost and down time in developing the overall repair program.
Elsewhere within the oil and gas industry as well as refining and petrochemicals, there exist many applications which would benefit from a large supply of high pressure inert medium. The primary use would be to purge hydrocarbon containing facilities including pipelines, gas plants, oil, batteries, tanks, refineries and petrochemical facilities.
U.S. Pat. No. 4,827,967 to Junier discloses a plug valve. A sealing assembly is for sealing off a space between a stem tube and guide tube of the plug valve in which the sealing assembly contains compressible packing. The present invention is completely different than this patent, since it is a system used for purging pipelines.
U.S. Pat. No. 5,174,323 to Haselden discloses a liquid material reservoir. A liquid material is transported from a holding or storage tank to the reservoir, so that the reservoir will distribute the liquid material, such as by gravity, to a distribution point within a system. The present invention is completely different than this patent, since it is a system used for purging pipelines.
U.S. Pat. No. 5,433,236 to Zollinger et al. Discloses an apparatus for moving a pipe inspection probe through piping. The apparatus uses a precise application of a pressure differential to maneuver an inspection device through piping, rather than using cables to pull or push the inspection device through the piping. The present invention utilizes an exhaust gas from a power turbine for pipeline purging which is different than this patent.
U.S. Pat. No. 5,444,886 to Takashina et al. discloses an apparatus for cleaning a piping. A pig is reciprocated within a pipe conduit, so that the interior of the pipe conduit can be efficiently cleaned. This patent uses compressed gas to move the pig through the pipe conduit. The present invention uses the exhaust gas from the power turbine for this purpose.
U.S. Pat. No. 5,531,240 to Kelada discloses a method and apparatus for spill free liquid transfer. A portable or a fixed system safely transfers regulated and environmentally hazardous liquids from top or bottom connections of a source container, pipe or equipment to a receiving vessel without retaining liquid in connecting pipes that may spill and contaminate the environment when the pipes are disconnected. This patent utilizes a pressurized inert gas to transfer the liquids, while the present invention uses exhaust gas to purge pipelines.
U.S. Pat. No. 5,577,528 to Saha et al. Discloses an apparatus for upgrade or repair of in-service pipelines. The apparatus has a built-in repairing mechanism for repairing a pipeline section and does not require taking such pipeline section out of service and does not require construction of a separate bypass around pipe sections upgraded or repaired. The present invention is different than this patent since it uses an exhaust gas from a power turbine to purge pipelines, so that the pipelines can be repaired.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.